Configuration of beam pair links during random access

ABSTRACT

Methods and apparatus are provided for configuring beam pair links during random access. A User Equipment (UE) receives, in a first message of a Random Access Channel (RACH) procedure, a request from a Base Station (BS) to report information relating to a plurality of BS beams. The UE reports, in a second message of the RACH procedure, the information relating to one or more of the plurality of BS beams in response to the request. The UE receives configuration information including information relating to one or more beam pair links configured for communication between the UE and the BS based on the reported information.

This application claims priority to U.S. Provisional Application Ser.No. 62/532,903, entitled “CONFIGURATION OF BEAM PAIR LINKS DURING RANDOMACCESS”, filed on Jul. 14, 2017, which is expressly incorporated byreference in its entirety.

FIELD

The present disclosure relates generally to wireless communicationsystems, and more particularly, to methods and apparatus forconfiguration of beam pair links during random access.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includeLong Term Evolution (LTE) systems, code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipment (UEs). In LTE or LTE-A network, a set of one or more basestations may define an eNodeB (eNB). In other examples (e.g., in a nextgeneration or 5^(th) generation (5G) network), a wireless multipleaccess communication system may include a number of distributed units(DUs) (e.g., edge units (EUs), edge nodes (ENs), radio heads (RHs),smart radio heads (SRHs), transmission reception points (TRPs), etc.) incommunication with a number of central units (CUs) (e.g., central nodes(CNs), access node controllers (ANCs), etc.), where a set of one or moredistributed units, in communication with a central unit, may define anaccess node (e.g., a new radio base station (NR BS), a new radio node-B(NR NB), a network node, 5G NB, eNB, etc.). A base station or DU maycommunicate with a set of UEs on downlink channels (e.g., fortransmissions from a base station or to a UE) and uplink channels (e.g.,for transmissions from a UE to a base station or distributed unit).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is new radio (NR), for example, 5G radioaccess. NR is a set of enhancements to the LTE mobile standardpromulgated by Third Generation Partnership Project (3GPP). It isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingOFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink(UL) as well as support beamforming, multiple-input multiple-output(MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a desire for further improvements in NRtechnology. Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a User Equipment (UE). The method generally includesreceiving, in a first message of a Random Access Channel (RACH)procedure, a request from a Base Station (BS) to report informationrelating to a plurality of BS beams, reporting, in a second message ofthe RACH procedure, the information relating to one or more of theplurality of BS beams in response to the request, and receivingconfiguration information including information relating to one or morebeam pair links configured for communication between the UE and the BSbased on the reported information.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a source Base Station (BS). The method generallyincludes transmitting, to a User Equipment (UE) in a first message of aRandom Access Channel (RACH) procedure, a request to report informationrelating to a plurality of BS beams, receiving, from the UE in a secondmessage of the RACH procedure, the information relating to one or moreof the plurality of BS beams in response to the request, andtransmitting configuration information including information relating toone or more beam pair links configured for communication between the UEand the BS, the one or more beam pair links configured based on thereceived information.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a User Equipment (UE). The method generally includesreceiving, in a first message of a Random Access Channel (RACH)procedure, a request from a Base Station (BS) to report informationrelating to a plurality of BS beams, wherein the first message furtherincludes configuration information including a configuration forestablishing one or more beam pair links for communication between theUE and the BS, reporting, in a second message of the RACH procedure, theinformation relating to one or more of the plurality of BS beams inresponse to the request, and using one or more of the reported BS beamsfor communication between the UE and the BS based on the receivedconfiguration information.

Certain aspects of the present disclosure provide a method for wirelesscommunications by a source Base Station (BS). The method generallyincludes transmitting, in a first message of a Random Access Channel(RACH) procedure, a request from a Base Station (BS) to reportinformation relating to a plurality of BS beams, wherein the firstmessage further includes configuration information including aconfiguration for establishing one or more beam pair links forcommunication between the UE and the BS, receiving, in a second messageof the RACH procedure, information relating to reported one or more ofthe plurality of BS beams in response to the request, and using one ormore of the reported BS beams for communication between the UE and theBS based on the transmitted configuration information.

Aspects generally include methods, apparatus, systems, computer readablemediums, and processing systems, as substantially described herein withreference to and as illustrated by the accompanying drawings.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample BS and user equipment (UE), in accordance with certain aspectsof the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a downlink-centric (DL-centric)subframe, in accordance with certain aspects of the present disclosure.

FIG. 7 illustrates an example of an uplink-centric (UL-centric)subframe, in accordance with certain aspects of the present disclosure.

FIG. 8 illustrates example operations 800 that may be performed by a UEfor configuration of one or more beam pair links, in accordance withcertain aspects of the present disclosure.

FIG. 9 illustrates example operations 900 that may be performed by a BS(e.g., a gNB) for configuration of one or more beam pair links, inaccordance with certain aspects of the present disclosure.

FIG. 10 illustrates example operations 1000 performed by a UE forconfiguration of one or more beam pair links, in accordance with certainaspects of the present disclosure.

FIG. 11 illustrates example operations 1100 performed by a BS (e.g.,gNB) for configuration of one or more beam pair links, in accordancewith certain aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

For initial cell acquisition, a UE generally listens to broadcastedsignals, for example, including Primary Synchronization Signal (PSS),Secondary Synchronization Signal (SSS), Extended Synchronization Signal(ESS), Demodulation Reference Signal (e.g., for PBCH) and PhysicalBroadcast Channel (PBCH). The broadcasted signals are generally carriedover directional beams. The UE, based on the synchronization signals andother reference signals transmitted by a Node B, selects a cell and beamwithin the cell. After camping on the cell, the UE receives and decodessystem information including parameters for performing a Random AccessChannel (RACH) procedure. The UE then performs a RACH procedure (e.g.,contention based RACH procedure) on the selected cell using the beampair determined based on the received synchronization signals.

One limitation of the RACH procedure is that due to user mobility,rotation or signal blockage, beam characteristics change over time. Thismay cause beam failure, which in turn may result in retransmissionsand/or RACH failure. Thus, a beam pair link (e.g., including a BS Tx-Rxbeam and a UE Tx-Rx beam) selected by the UE for initial access (e.g.,based on synchronization signals) may not be optimal.

Certain aspects of the present disclosure discuss techniques toconfigure one or more alternative beam pair links between a Node B and aUE for exchange of control and/or data to enhance reliability. Incertain aspects, the UE may report information regarding a plurality ofbase station (BS) beams during initial access and the BS, based on thereported information, may configure one or more beam pair links forcommunication between the BS and the UE. In certain aspects, thistechnique provides the UE with alternative beam pair links for use withthe BS, and makes control and data exchange between the UE and the BSmore reliable.

NR may support various wireless communication services, such as Enhancedmobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond),millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz),massive MTC (mMTC) targeting non-backward compatible MTC techniques,and/or mission critical targeting ultra-reliable low latencycommunications (URLLC). These services may include latency andreliability requirements. These services may also have differenttransmission time intervals (TTI) to meet respective quality of service(QoS) requirements. In addition, these services may co-exist in the samesubframe.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication networks such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as NR (e.g. 5GRA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA andE-UTRA are part of Universal Mobile Telecommunication System (UMTS). NRis an emerging wireless communications technology under development inconjunction with the 5G Technology Forum (5GTF). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that useE-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

EXAMPLE WIRELESS COMMUNICATIONS SYSTEM

FIG. 1 illustrates an example wireless network 100, such as a new radio(NR) or 5G network, in which aspects of the present disclosure may beperformed.

As illustrated in FIG. 1, the wireless network 100 may include a numberof BSs 110 and other network entities. A BS may be a station thatcommunicates with UEs. Each BS 110 may provide communication coveragefor a particular geographic area. In 3GPP, the term “cell” can refer toa coverage area of a Node B and/or a Node B subsystem serving thiscoverage area, depending on the context in which the term is used. In NRsystems, the term “cell” and eNB, Node B, 5G NB, AP, NR BS, NR BS, orTRP may be interchangeable. In some examples, a cell may not necessarilybe stationary, and the geographic area of the cell may move according tothe location of a mobile base station. In some examples, the basestations may be interconnected to one another and/or to one or moreother base stations or network nodes (not shown) in the wireless network100 through various types of backhaul interfaces such as a directphysical connection, a virtual network, or the like using any suitabletransport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a frequencychannel, etc. Each frequency may support a single RAT in a givengeographic area in order to avoid interference between wireless networksof different RATs. In some cases, NR or 5G RAT networks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). A BS for a macro cell may be referred to as a macro BS. A BS fora pico cell may be referred to as a pico BS. A BS for a femto cell maybe referred to as a femto BS or a home BS. In the example shown in FIG.1, the BSs 110 a, 110 b and 110 c may be macro BSs for the macro cells102 a, 102 b and 102 c, respectively. The BS 110 x may be a pico BS fora pico cell 102 x. The BSs 110 y and 110 z may be femto BS for the femtocells 102 y and 102 z, respectively. A BS may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., a BS or a UE) and sends atransmission of the data and/or other information to a downstreamstation (e.g., a UE or a BS). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the BS 110 a and a UE 120 r inorder to facilitate communication between the BS 110 a and the UE 120 r.A relay station may also be referred to as a relay BS, a relay, etc.

The wireless network 100 may be a heterogeneous network that includesBSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference in thewireless network 100. For example, macro BS may have a high transmitpower level (e.g., 20 Watts) whereas pico BS, femto BS, and relays mayhave a lower transmit power level (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the BSs may have similar frametiming, and transmissions from different BSs may be approximatelyaligned in time. For asynchronous operation, the BSs may have differentframe timing, and transmissions from different BSs may not be aligned intime. The techniques described herein may be used for both synchronousand asynchronous operation.

A network controller 130 may be coupled to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another, e.g., directly or indirectly via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a mobile station, a terminal, an access terminal,a subscriber unit, a station, a Customer Premises Equipment (CPE), acellular phone, a smart phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, a medical device or medical equipment, a biometricsensor/device, a wearable device such as a smart watch, smart clothing,smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, asmart bracelet, etc.), an entertainment device (e.g., a music device, avideo device, a satellite radio, etc.), a vehicular component or sensor,a smart meter/sensor, industrial manufacturing equipment, a globalpositioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. Some UEs maybe considered evolved or machine-type communication (MTC) devices orevolved MTC (eMTC) devices. MTC and eMTC UEs include, for example,robots, drones, remote devices, sensors, meters, monitors, locationtags, etc., that may communicate with a BS, another device (e.g., remotedevice), or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things (IoT) devices. InFIG. 1, a solid line with double arrows indicates desired transmissionsbetween a UE and a serving BS, which is a BS designated to serve the UEon the downlink and/or uplink. A dashed line with double arrowsindicates interfering transmissions between a UE and a BS.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth (e.g., system frequency band) intomultiple (K) orthogonal subcarriers, which are also commonly referred toas tones, bins, etc. Each subcarrier may be modulated with data. Ingeneral, modulation symbols are sent in the frequency domain with OFDMand in the time domain with SC-FDM. The spacing between adjacentsubcarriers may be fixed, and the total number of subcarriers (K) may bedependent on the system bandwidth. For example, the spacing of thesubcarriers may be 15 kHz and the minimum resource allocation (called a‘resource block’) may be 12 subcarriers (or 180 kHz). Consequently, thenominal FFT size may be equal to 128, 256, 512, 1024 or 2048 for systembandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz), respectively. Thesystem bandwidth may also be partitioned into subbands. For example, asubband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be1, 2, 4, 8 or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR. NR may utilizeOFDM with a CP on the uplink and downlink and include support forhalf-duplex operation using time division duplex (TDD). A singlecomponent carrier bandwidth of 100 MHz may be supported. NR resourceblocks may span 12 sub-carriers with a sub-carrier bandwidth of 75 kHzover a 0.1 ms duration. Each radio frame may consist of 50 subframeswith a length of 10 ms. Consequently, each subframe may have a length of0.2 ms. Each subframe may indicate a link direction (i.e., DL or UL) fordata transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data. UL and DL subframes for NR may be as described inmore detail below with respect to FIGS. 6 and 7. Beamforming may besupported and beam direction may be dynamically configured. MIMOtransmissions with precoding may also be supported. MIMO configurationsin the DL may support up to 8 transmit antennas with multi-layer DLtransmissions up to 8 streams and up to 2 streams per UE. Multi-layertransmissions with up to 2 streams per UE may be supported. Aggregationof multiple cells may be supported with up to 8 serving cells.Alternatively, NR may support a different air interface, other than anOFDM-based. NR networks may include entities such CUs and/or DUs.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. Base stations arenot the only entities that may function as a scheduling entity. That is,in some examples, a UE may function as a scheduling entity, schedulingresources for one or more subordinate entities (e.g., one or more otherUEs). In this example, the UE is functioning as a scheduling entity, andother UEs utilize resources scheduled by the UE for wirelesscommunication. A UE may function as a scheduling entity in apeer-to-peer (P2P) network, and/or in a mesh network. In a mesh networkexample, UEs may optionally communicate directly with one another inaddition to communicating with the scheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., eNB, 5GNode B, Node B, transmission reception point (TRP), access point (AP))may correspond to one or multiple BSs. NR cells can be configured asaccess cell (ACells) or data only cells (DCells). For example, the RAN(e.g., a central unit or distributed unit) can configure the cells.DCells may be cells used for carrier aggregation or dual connectivity,but not used for initial access, cell selection/reselection, orhandover. In some cases DCells may not transmit synchronizationsignals—in some case cases DCells may transmit SS. NR BSs may transmitdownlink signals to UEs indicating the cell type. Based on the cell typeindication, the UE may communicate with the NR BS. For example, the UEmay determine NR BSs to consider for cell selection, access, handover,and/or measurement based on the indicated cell type.

FIG. 2 illustrates an example logical architecture of a distributedradio access network (RAN) 200, which may be implemented in the wirelesscommunication system illustrated in FIG. 1. A 5G access node 206 mayinclude an access node controller (ANC) 202. The ANC may be a centralunit (CU) of the distributed RAN 200. The backhaul interface to the nextgeneration core network (NG-CN) 204 may terminate at the ANC. Thebackhaul interface to neighboring next generation access nodes (NG-ANs)may terminate at the ANC. The ANC may include one or more TRPs 208(which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, orsome other term). As described above, a TRP may be used interchangeablywith “cell.”

The TRPs 208 may be a DU. The TRPs may be connected to one ANC (ANC 202)or more than one ANC (not illustrated). For example, for RAN sharing,radio as a service (RaaS), and service specific AND deployments, the TRPmay be connected to more than one ANC. A TRP may include one or moreantenna ports. The TRPs may be configured to individually (e.g., dynamicselection) or jointly (e.g., joint transmission) serve traffic to a UE.

The local architecture 200 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 210 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 208. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 202. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture 200. As will be described in moredetail with reference to FIG. 5, the Radio Resource Control (RRC) layer,Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC)layer, Medium Access Control (MAC) layer, and a Physical (PHY) layersmay be adaptably placed at the DU or CU (e.g., TRP or ANC,respectively). According to certain aspects, a BS may include a centralunit (CU) (e.g., ANC 202) and/or one or more distributed units (e.g.,one or more TRPs 208).

FIG. 3 illustrates an example physical architecture of a distributed RAN300, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 302 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A DU 306 may host one or more TRPs (edge node (EN), an edge unit (EU), aradio head (RH), a smart radio head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of the BS 110 and UE 120illustrated in FIG. 1, which may be used to implement aspects of thepresent disclosure. As described above, the BS may include a TRP. One ormore components of the BS 110 and UE 120 may be used to practice aspectsof the present disclosure. For example, antennas 452, Tx/Rx 222,processors 466, 458, 464, and/or controller/processor 480 of the UE 120and/or antennas 434, processors 460, 420, 438, and/orcontroller/processor 440 of the BS 110 may be used to perform theoperations described herein and illustrated with reference to FIGS. 8-9.

FIG. 4 shows a block diagram of a design of a BS 110 and a UE 120, whichmay be one of the BSs and one of the UEs in FIG. 1. For a restrictedassociation scenario, the base station 110 may be the macro BS 110 c inFIG. 1, and the UE 120 may be the UE 120 y. The base station 110 mayalso be a base station of some other type. The base station 110 may beequipped with antennas 434 a through 434 t, and the UE 120 may beequipped with antennas 452 a through 452 r.

At the base station 110, a transmit processor 420 may receive data froma data source 412 and control information from a controller/processor440. The control information may be for the Physical Broadcast Channel(PBCH), Physical Control Format Indicator Channel (PCFICH), PhysicalHybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel(PDCCH), etc. The data may be for the Physical Downlink Shared Channel(PDSCH), etc. The processor 420 may process (e.g., encode and symbolmap) the data and control information to obtain data symbols and controlsymbols, respectively. The processor 420 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 430 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 432 a through 432t. For example, the TX MIMO processor 430 may perform certain aspectsdescribed herein for RS multiplexing. Each modulator 432 may process arespective output symbol stream (e.g., for OFDM, etc.) to obtain anoutput sample stream. Each modulator 432 may further process (e.g.,convert to analog, amplify, filter, and upconvert) the output samplestream to obtain a downlink signal. Downlink signals from modulators 432a through 432 t may be transmitted via the antennas 434 a through 434 t,respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) 454 a through 454 r, respectively. Eachdemodulator 454 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 454 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 456 may obtainreceived symbols from all the demodulators 454 a through 454 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. For example, MIMO detector 456 may provide detected RStransmitted using techniques described herein. A receive processor 458may process (e.g., demodulate, deinterleave, and decode) the detectedsymbols, provide decoded data for the UE 120 to a data sink 460, andprovide decoded control information to a controller/processor 480.According to one or more cases, CoMP aspects can include providing theantennas, as well as some Tx/Rx functionalities, such that they residein distributed units. For example, some Tx/Rx processings can be done inthe central unit, while other processing can be done at the distributedunits. For example, in accordance with one or more aspects as shown inthe diagram, the BS mod/demod 432 may be in the distributed units.

On the uplink, at the UE 120, a transmit processor 464 may receive andprocess data (e.g., for the Physical Uplink Shared Channel (PUSCH)) froma data source 462 and control information (e.g., for the Physical UplinkControl Channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a referencesignal. The symbols from the transmit processor 464 may be precoded by aTX MIMO processor 466 if applicable, further processed by thedemodulators 454 a through 454 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 110. At the BS 110, the uplink signalsfrom the UE 120 may be received by the antennas 434, processed by themodulators 432, detected by a MIMO detector 436 if applicable, andfurther processed by a receive processor 438 to obtain decoded data andcontrol information sent by the UE 120. The receive processor 438 mayprovide the decoded data to a data sink 439 and the decoded controlinformation to the controller/processor 440.

The controllers/processors 440 and 480 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 440 and/orother processors and modules at the base station 110 may perform ordirect, e.g., the execution of the functional blocks illustrated in FIG.10, and/or other processes for the techniques described herein. Theprocessor 480 and/or other processors and modules at the UE 120 may alsoperform or direct processes for the techniques described herein. Thememories 442 and 482 may store data and program codes for the BS 110 andthe UE 120, respectively. A scheduler 444 may schedule UEs for datatransmission on the downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a in a 5G system (e.g., a systemthat supports uplink-based mobility). Diagram 500 illustrates acommunications protocol stack including a Radio Resource Control (RRC)layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a RadioLink Control (RLC) layer 520, a Medium Access Control (MAC) layer 525,and a Physical (PHY) layer 530. In various examples the layers of aprotocol stack may be implemented as separate modules of software,portions of a processor or ASIC, portions of non-collocated devicesconnected by a communications link, or various combinations thereof.Collocated and non-collocated implementations may be used, for example,in a protocol stack for a network access device (e.g., ANs, CUs, and/orDUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device (e.g., access node (AN), new radio base station (NR BS), anew radio Node-B (NR NB), a network node (NN), or the like.). In thesecond option, the RRC layer 510, the PDCP layer 515, the RLC layer 520,the MAC layer 525, and the PHY layer 530 may each be implemented by theAN. The second option 505-b may be useful in a femto cell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack (e.g., theRRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525,and the PHY layer 530).

FIG. 6 is a diagram 600 showing an example of a DL-centric subframe. TheDL-centric subframe may include a control portion 602. The controlportion 602 may exist in the initial or beginning portion of theDL-centric subframe. The control portion 602 may include variousscheduling information and/or control information corresponding tovarious portions of the DL-centric subframe. In some configurations, thecontrol portion 602 may be a physical DL control channel (PDCCH), asindicated in FIG. 6. The DL-centric subframe may also include a DL dataportion 604. The DL data portion 604 may sometimes be referred to as thepayload of the DL-centric subframe. The DL data portion 604 may includethe communication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 604 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include a common UL portion 606. Thecommon UL portion 606 may sometimes be referred to as an UL burst, acommon UL burst, and/or various other suitable terms. The common ULportion 606 may include feedback information corresponding to variousother portions of the DL-centric subframe. For example, the common ULportion 606 may include feedback information corresponding to thecontrol portion 602. Non-limiting examples of feedback information mayinclude an ACK signal, a NACK signal, a HARQ indicator, and/or variousother suitable types of information. The common UL portion 606 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests (SRs), and various other suitable types of information. Asillustrated in FIG. 6, the end of the DL data portion 604 may beseparated in time from the beginning of the common UL portion 606. Thistime separation may sometimes be referred to as a gap, a guard period, aguard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the subordinate entity (e.g., UE)) to UL communication(e.g., transmission by the subordinate entity (e.g., UE)). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 7 is a diagram 700 showing an example of an UL-centric subframe.The UL-centric subframe may include a control portion 702. The controlportion 702 may exist in the initial or beginning portion of theUL-centric subframe. The control portion 702 in FIG. 7 may be similar tothe control portion described above with reference to FIG. 6. TheUL-centric subframe may also include an UL data portion 704. The UL dataportion 704 may sometimes be referred to as the payload of theUL-centric subframe. The UL data portion may refer to the communicationresources utilized to communicate UL data from the subordinate entity(e.g., UE) to the scheduling entity (e.g., UE or BS). In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH).

As illustrated in FIG. 7, the end of the control portion 702 may beseparated in time from the beginning of the UL data portion 704. Thistime separation may sometimes be referred to as a gap, guard period,guard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). The UL-centric subframe may alsoinclude a common UL portion 706. The common UL portion 706 in FIG. 7 maybe similar to the common UL portion 706 described above with referenceto FIG. 7. The common UL portion 706 may additionally or alternativelyinclude information pertaining to channel quality indicator (CQI),sounding reference signals (SRSs), and various other suitable types ofinformation. One of ordinary skill in the art will understand that theforegoing is merely one example of an UL-centric subframe andalternative structures having similar features may exist withoutnecessarily deviating from the aspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

EXAMPLE CONFIGURATION OF BEAM PAIR LINKS DURING RANDOM ACCESS

For initial cell acquisition, a UE generally listens to broadcastedsignals, for example, including Primary Synchronization Signal (PSS),Secondary Synchronization Signal (SSS), Extended Synchronization Signal(ESS), Demodulation Reference Signal (e.g., DMRS for PBCH) and PhysicalBroadcast Channel (PBCH). The broadcasted signals are generally carriedover directional beams. The UE, based on the synchronization signals andother reference signals transmitted by a Node B, selects a cell and beamwithin the cell. After camping on the cell, the UE receives and decodessystem information including parameters for performing a Random AccessChannel (RACH) procedure. The UE then performs a RACH procedure (e.g.,contention based RACH procedure) on the selected cell using a beam pairdetermined based on the received synchronization signals.

A typical RACH procedure (e.g., similar to LTE RACH procedure) mayinclude the UE transmitting a message 1 including a RACH preamble to theNode B. For transmission of message 1, the UE selects a preamblesequence (e.g., based on system information). The UE also selects aresource (e.g., a symbol index, for example, a RACH opportunity insubframe m), a frequency band within a system bandwidth, and calculatestransmit power for the transmission of message 1. In an aspect, the UEuses the same antenna subarray and beam for the transmission of message1 that was used when samples of the beam were detected and selected whenreceiving synchronization signals.

At the network, the Node B monitors a corresponding receive (Rx) beamfor the preamble sequence and receives the preamble sequence. Afterreceiving the preamble sequence in message 1, the Node B transmits aPDCCH with an associated Randol Access Radio Network TemporaryIdentifier (RA-RNTI) to the UE. The Node B also transmits acorresponding PDSCH that includes message 2 of the RACH procedure. Thisconstitutes a Random Access Response. Generally, at the Node B it isassumed that the PDCCH and the PDSCH use the same transmit (Tx)beam/port that was used to receive message 1.

For message 2 reception, the UE may use the same antenna subarray andbeam that was used for messagel transmission or with some refinement. Inan aspect, UE monitors PDCCH for message 2 identified by the RA-RNTI inthe RA Response window (RAR window) that starts at the subframe (SF)that includes the end of the preamble transmission+N SF (e.g, N is aninteger), and has a length of ra-ResponseWindowSize which is generallyrepresented as a number of subframes. In an aspect, the parameterra-ResponseWiSSndowSize is broadcast in SIB 2.

Following message 2, UE and Node B exchange messages 3 and 4 to completethe RACH procedure.

One limitation of the RACH procedure is that due to user mobility,rotation or signal blockage, beam characteristics change over time. Thismay cause beam failure, which in turn may result in retransmissionsand/or RACH failure. Thus, a beam pair link (e.g., including a BS Tx-Rxbeam and a UE Tx-Rx beam) selected by the UE for initial access (e.g.,based on synchronization signals) may not be optimal.

Certain aspects of the present disclosure discuss techniques toconfigure one or more alternative beam pair links between a Node B and aUE for exchange of control and/or data (e.g., PDCCH, PDSCH, PUCCH,PUSCH) to enhance reliability. In certain aspects, the UE may reportinformation regarding a plurality of base station (BS) beams duringinitial access and the BS, based on the reported information, mayconfigure one or more beam pair links for communication between the BSand the UE. In certain aspects, this technique provides the UE withalternative beam pair links for use with the BS, and makes control anddata exchange between the UE and the BS more reliable.

In certain aspects, a BS may request a UE, during a RACH procedure, toreport information regarding a plurality of BS beams. The UE may reportone or more BS beams in response to the network request. The network mayconfigure one or more beam pair links for communication between the UEand the BS based on the UE reports. Once configured, the one or moreconfigured beam pair links may be used by the BS and the UE to exchangecontrol and data messages.

FIG. 8 illustrates example operations 800 that may be performed by a UEfor configuration of one or more beam pair links, in accordance withcertain aspects of the present disclosure.

Operations 800 begin, at 802, by receiving, in a first message of a RACHprocedure, a request from a BS to report information relating to aplurality of BS beams. At 802, the UE reports, in a second message ofthe RACH procedure, the information relating to one or more of theplurality of BS beams in response to the request. At 806, the UEreceives configuration information including information relating to oneor more beam pair links configured for communication between the UE andthe BS based on the reported information.

FIG. 9 illustrates example operations 900 that may be performed by a BS(e.g., a gNB) for configuration of one or more beam pair links, inaccordance with certain aspects of the present disclosure.

Operations 900 begin, at 902, by transmitting, to a UE in a firstmessage of a RACH procedure, a request to report information relating toa plurality of BS beams. At 904, the BS receives, from the UE in asecond message of the RACH procedure, the information relating to one ormore of the plurality of BS beams in response to the request. At 906,the BS transmits configuration information including informationrelating to one or more beam pair links configured for communicationbetween the UE and the BS, the one or more beam pair links configuredbased on the received information.

In an aspect, the first message and second message in operations 800 and900 correspond to message 2 and message 3 respectively of a typical RACHprocedure.

In certain aspects, the BS may include the request for reportinginformation relating to the plurality of BS beams in message 2 of theRACH procedure. In an aspect, this request may be based on BS uplinkmeasurements of the PRACH (Physical Random Access Channel). In responseto the request, the UE may report information regarding one or more BSbeams, as received at the UE, in message 3 of the RACH procedure. In anaspect, the BS may request the UE to report up to N BS beams and the UEmay report M BS beams, wherein M<=N. For example, the BS may request theUE to report the top N BS beams (e.g., based on the transmit powers ofthe BS beams). However, the UE may report only a subset (e.g., M BSbeams) as seen by the UE. In an aspect, for contention based RACHprocedure, the BS may not include the identity of particular BS beams tobe measured by the UE. Instead, the UE decides which BS beams to report,for example, based on received signal strengths of the received BSbeams.

In certain aspects, the information regarding the one or more BS beamsreported by the UE may include a beam ID of each reported BS beam and acorresponding signal strength of the beam as measured by the UE.

In certain aspects, the UE may report beam group sets, each beam groupset including one or more BS beams as measured by an antenna subarray atthe UE. The UE may use a certain antenna subarray to measure multiple BSbeams. The UE may report measurements of multiple BS beams as measuredby the particular antenna subarray. For example, the UE may form twobeam groups, beam group 0 and beam group 1 in two different directionsusing two different antenna subarrays. The UE may measure four BS beamsin beam group 0 direction and 5 BS beams in beam group 1 direction usingthe respective antenna subarrays. The UE may report the four BS beams asbeam group 0 and the five BS beams as beam group 1. The UE may use thesame antenna subarray/beam for each of the BS beams in a beam group.

In an aspect, the reporting by the UE of the information relating to oneor more BS beams may be based on a service type, a quality of service,or other metric, for example, including a mobility state of the UE(e.g., high speed) of the UE.

In certain aspects, the BS, based on the information received from theUE (e.g., measurements relating to the BS beams), may configure one ormore beam pair links to be used for exchanging control and data signalsbetween the UE and the BS. In an aspect, the BS may transmit theconfiguration information relating to the beam pair links in message 4of the RACH procedure, or anytime after receiving message 3 from the UE.In an aspect, the configured beam pair links may be used for PDCCH,PDSCH, PUCCH and PUSCH. In an aspect, in addition to the measurements ofthe reported BS beams, the UE may also include in message 3 informationregarding the service type, quality of service and/or mobility status ofthe UE. The BS may take this additional information into considerationwhen deciding which beam pair link(s) to configure for communicationbetween the UE and the BS.

In certain aspects, the information relating to configuration of the oneor more beam pair links transmitted to the UE may include an identity ofeach configured BS beam. In an aspect, the UE knows the identity of eachBS beam it reported and the UE beam/antenna subarray it used forreceiving the BS beam. Thus, in an aspect, the UE may determine which UEbeam corresponds to a BS beam configured by the BS and may use the UEbeam in combination with the configured BS beam as a beam pair link forexchanging control and data signals with the BS.

In certain aspects, if the BS configures a BS beam from a BS beam groupreported by the UE, the UE knows which antenna subarray/beam group theconfigured BS beam corresponds to, and may use the antenna subarray withthe configured BS beam for communication with the BS. In an aspect, theconfiguration information from the BS may include an identification ofthe UE beam group that corresponds to a configured BS.

In certain aspects, the configuration information relating to theconfigured beam pair links transmitted by the BS may include informationregarding the time resource(s) over which each configured beam pair linkis to be used for communication between the BS and the UE. For example,the network may schedule control or data using one of the configuredbeam pair links (e.g., using a corresponding beam ID) in slot N+K (whereN and K are integers). In another example, in case of scheduling BSbeams from reported beam groups, the network may tell the UE that inslot N+K it is going to schedule control or data using one of the BSbeams (e.g., using beam ID) for UE beam group 0. For example,configuration information may include scheduling of BS beam 1 of UE beamgroup 0 of the measurement report in slot N+K1, and scheduling of BSbeam 3 of UE beam group 1 in slot N+K2 (e.g., in TDM fashion). Or forFDM fashion, in slot N+K scheduling FDMed BS beams 1 and 3 of UE beamgroups 0 and 1 respectively. The UE may use the configured beam pairlinks in the scheduled slots to transmit/receive control and/or datasignals.

In certain aspects, message 4 of the RACH procedure transmitted by theBS may further include further configuration information includingtransmission configuration to be used for exchanging control and/or datasubsequent to configuration of the beam pair link(s). Additionally oralternatively, the transmission configuration may be carried by message2 of the RACH procedure and/or broadcasted in a broadcast channel likePBCH or included in SIB, or on-demand SIB requested by the UE. In anaspect, the transmission configuration may be used for message 4 of theRACH procedure and any subsequent messages.

In certain aspects, the transmission configuration includes start andend times of at least one of PDCCH or PDSCH, for example, as a fractionof a nominal subframe including slots/minislots.

In certain aspects, the transmission configuration includes start andend times of at least one of PUCCH or PUSCH, for example, as a fractionof a nominal subframe including slots/minislots.

In certain aspects, the transmission configuration may include resourcepattern for usage of different beam pair links. For example, thetransmission configuration may include a TDM pattern specifying that afirst beam pair link is to be used in slot N+K1 and a second beam pairlink is to be used in slot N+K2, without actually specifying the actualbeam identities to be used in the slots. The BS and UE may assignparticular beam pair links for the TDM pattern based on beam pair linksconfigured by the BS using UE measurements.

In certain aspects, the transmission configuration may includeinformation regarding location of control channel transmission the UEneeds to monitor to decode PDSCH, or transmit PUSCH during accessprocedure in a nominal subframe.

In certain aspects, the transmission configuration includes a start timeand an end time of uplink control information when carried in PUCCH.

In certain aspects, the transmission configuration may includenumerology used for PDSCH and PUSCH. For example, the transmissionconfiguration may include a sub carrier spacing to be used for at leastone of PDSCH or PUSCH.

In certain aspects, the transmission configuration may include areference numerology used to define a nominal subframe duration. Forexample, a reference numerology may include 60 KHz tone spacing and 14symbols in 500 μs.

In certain aspects, the techniques discussed above may be used forcontention based random access, contention free random access, initialaccess and handover scenarios. For example, in contention free randomaccess, instead of using message 3 and message 4, PUCCH/PUSCH andPDCCH/PDSCH may be used.

In certain aspects, the network may transmit (e.g., in message 2 of RACHprocedure or SI) a configuration for establishing one or more beam pairlinks for communication between the UE and the BS. For example, thenetwork informs the UE (in message 2 or SI) that it intends to configuretwo beam pair links. The UE may report one or more BS beams. If the UEreports one BS beam the network uses the reported beam for configuringone beam pair link and uses the configured beam pair link for message 4and onwards. If the UE reports two BS beams, the BS configures two beampair links using the two reported beams. If, the UE reports more thantwo BS beams, the network uses the top two beams (e.g., having highestsignal strength) for configuring the two beam pair links (e.g., topreported beam as beam pair link 1 and second highest as beam pair link2). The UE knows from message 2 or SI how many beam pair links thenetwork intends to configure, and based on its reported BS beams knowswhich beams to use for communication with the BS. For example, there isan implicit mapping between the top reported BS beam (e.g., havinghighest signal strength) to beam pair link 1 and second highest BS beam(e.g., having second highest signal strength) to beam pair link 2. Thus,both BS and UE know which BS beams map to which configured beam pairlinks and communicate accordingly. In this case, there is no need forthe network to explicitly inform the UE of the beam pair linksconfigured for communication between the UE and the BS.

In certain aspects, the message 2 of the RACH procedure, in addition tothe request to measure and report BS beams, may include a configurationfor establishing one or more beam pair links for communication betweenthe UE and the BS.

FIG. 10 illustrates example operations 1000 performed by a UE forconfiguration of one or more beam pair links, in accordance with certainaspects of the present disclosure.

Operations 1000 begin, at 1002, by receiving, in a first message of aRACH procedure, a request from a Base Station (BS) to report informationrelating to a plurality of BS beams, wherein the first message furtherincludes configuration information including a configuration forestablishing one or more beam pair links for communication between theUE and the BS. For example, the configuration information includes anumber of beam pair links the network intends to establish forcommunication between the UE and the BS. At 1004, the UE reports, in asecond message of the RACH procedure, the information relating to one ormore of the plurality of BS beams in response to the request. At 1006,the UE uses one or more of the reported BS beams for communicationbetween the UE and the BS based on the received configurationinformation.

FIG. 11 illustrates example operations 1100 performed by a BS (e.g.,gNB) for configuration of one or more beam pair links, in accordancewith certain aspects of the present disclosure.

Operations 1100 being, at 1102 by transmitting, in a first message of aRACH procedure, a request from a Base Station (BS) to report informationrelating to a plurality of BS beams, wherein the first message furtherincludes configuration information including a configuration forestablishing one or more beam pair links for communication between theUE and the BS. At 1104, the BS receives, in a second message of the RACHprocedure, information relating to reported one or more of the pluralityof BS beams in response to the request. At 1106, the BS uses one or moreof the reported BS beams for communication between the UE and the BSbased on the transmitted configuration information.

In an aspect, the first message and the second message in operations1000 and 1100 correspond to message 2 and message 3 respectively of atypical RACH procedure.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering.

For example, means for transmitting and/or means for receiving maycomprise one or more of a transmit processor 420, a TX MIMO processor430, a receive processor 438, or antenna(s) 434 of the base station 110and/or the transmit processor 464, a TX MIMO processor 466, a receiveprocessor 458, or antenna(s) 452 of the user equipment 120.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communication by a UserEquipment (UE), comprising: receiving, in a first message of a RandomAccess Channel (RACH) procedure, a request from a Base Station (BS) toreport information relating to a plurality of BS beams; reporting, in asecond message of the RACH procedure, the information relating to one ormore of the plurality of BS beams in response to the request; andreceiving configuration information including information relating toone or more beam pair links configured for communication between the UEand the BS based on the reported information.
 2. The method of claim 1,wherein the information relating to the one or more BS beams includes anidentification of each reported BS beam and a corresponding signalstrength of the BS beam as measured by the UE.
 3. The method of claim 2,wherein the information relating to the one or more BS beams includesinformation regarding at least one beam group at the UE, each beam groupincludes one or more BS beams as measured by a different antennasub-array at the UE.
 4. The method of claim 1, wherein the informationrelating to the one or more BS beams is based on at least one of aservice type, a quality of service, or a mobility state of the UE. 5.The method of claim 4, wherein the information relating to the one ormore BS beams includes information relating to at least one of theservice type, the quality of service, or the mobility state of the UE.6. The method of claim 1, wherein the configuration information relatingto each of the beam pair links at least includes information regardingan identification of a BS beam to be used for the communication betweenthe UE and the BS.
 7. The method of claim 6, wherein the configurationinformation for the beam pair link further comprises an identificationof a beam group as reported by the UE.
 8. The method of claim 1, whereinthe configuration information for each beam pair link includes anindication of a time resource during which the beam pair link is to beused for the communication between the UE and the BS.
 9. The method ofclaim 1, further comprising using the configured one or more beam pairlinks to receive at least one of Physical Downlink Control Channel(PDCCH), Physical Downlink Shared Channel (PDSCH), or other referencesignals.
 10. The method of claim 1, further comprising using theconfigured one or more beam pair links to transmit at least one ofPhysical Uplink Control Channel (PUCCH) or Physical Uplink Data Channel(PUSCH).
 11. The method of claim 1, wherein the first message includesmessage 2 of the RACH procedure, the second message includes message 3of the RACH procedure.
 12. A method for wireless communication by a BaseStation (BS), comprising: transmitting, to a User Equipment (UE) in afirst message of a Random Access Channel (RACH) procedure, a request toreport information relating to a plurality of BS beams; receiving, fromthe UE in a second message of the RACH procedure, the informationrelating to one or more of the plurality of BS beams in response to therequest; and transmitting configuration information includinginformation relating to one or more beam pair links configured forcommunication between the UE and the BS, the one or more beam pair linksconfigured based on the received information.
 13. The method of claim12, wherein the information relating to the one or more BS beamsincludes an identification of each reported BS beam and a correspondingsignal strength of the BS beam as measured by the UE.
 14. The method ofclaim 13, wherein the information relating to the one or more BS beamsincludes information regarding at least one beam group at the UE, eachbeam group includes one or more BS beams as measured by a differentantenna sub-array at the UE.
 15. The method of claim 12, wherein theinformation relating to the one or more BS beams is based on at leastone of a service type, a quality of service, or a mobility state of theUE.
 16. The method of claim 15, wherein the information relating to theone or more BS beams includes information relating to at least one ofthe service type, the quality of service, or the mobility state of theUE.
 17. The method of claim 12, wherein the configuration informationrelating to each of the beam pair links at least includes informationregarding an identification of a BS beam to be used for thecommunication between the UE and the BS.
 18. The method of claim 17,wherein the configuration information for the beam pair link furthercomprises an identification of a beam group as reported by the UE. 19.The method of claim 12, wherein the configuration information for eachbeam pair link includes an indication of a time resource during whichthe beam pair link is to be used for the communication between the UEand the BS.
 20. The method of claim 12, further comprising using theconfigured one or more beam pair links to transmit at least one ofPhysical Downlink Control Channel (PDCCH), Physical Downlink SharedChannel (PDSCH), or other reference signals.
 21. The method of claim 12,further comprising using the configured one or more beam pair links toreceive at least one of Physical Uplink Control Channel (PUCCH) orPhysical Uplink Data Channel (PUSCH).
 22. The method of claim 12,wherein the first message includes message 2 of the RACH procedure, thesecond message includes message 3 of the RACH procedure.
 23. A methodfor wireless communication by a User Equipment (UE), comprising:receiving, in a first message of a Random Access Channel (RACH)procedure, a request from a Base Station (BS) to report informationrelating to a plurality of BS beams, wherein the first message furtherincludes configuration information including a configuration forestablishing one or more beam pair links for communication between theUE and the BS; reporting, in a second message of the RACH procedure, theinformation relating to one or more of the plurality of BS beams inresponse to the request; and using one or more of the reported BS beamsfor communication between the UE and the BS based on the receivedconfiguration information.
 24. The method of claim 23, wherein theinformation relating to the one or more BS beams includes anidentification of each reported BS beam and/or a corresponding signalstrength of the BS beam as measured by the UE.
 25. The method of claim23, wherein the information relating to the one or more BS beams isbased on at least one of a service type, a quality of service, or amobility state of the UE.
 26. The method of claim 23, whereincommunication between the UE and the BS receiving at least one ofPhysical Downlink Control Channel (PDCCH), Physical Downlink SharedChannel (PDSCH), or other reference signals.
 27. The method of claim 23,wherein communication between the UE and the BS includes transmitting atleast one of Physical Uplink Control Channel (PUCCH) or Physical UplinkData Channel (PUSCH).
 28. A method for wireless communication by a BaseStation (BS), comprising: transmitting, in a first message of a RandomAccess Channel (RACH) procedure, a request from a Base Station (BS) toreport information relating to a plurality of BS beams, wherein thefirst message further includes configuration information including aconfiguration for establishing one or more beam pair links forcommunication between the UE and the BS; receiving, in a second messageof the RACH procedure, information relating to reported one or more ofthe plurality of BS beams in response to the request; and using one ormore of the reported BS beams for communication between the UE and theBS based on the transmitted configuration information.
 29. The method ofclaim 28, wherein the information relating to the one or more BS beamsincludes an identification of each reported BS beam and a correspondingsignal strength of the BS beam as measured by the UE.
 30. The method ofclaim 28, wherein the information relating to the one or more BS beamsis based on at least one of a service type, a quality of service, or amobility state of the UE.